The AR 15 lower receiver is the part of the rifle (or pistol) that houses the fire control group (and lower parts kit), magazine well, and pistol grip. It attaches the buffer assembly and stock to an AR 15. That's the simple answer, but there is a bit more to go over. There are important legal definitions of what an AR 15 lower receiver actually is.
The stripped lower receiver is a firearm
The lower receiver is the only part of an AR 15 the ATF considers a firearm. Even without a barrel, stock, fire control group, or anything else, it's a firearm. This means a stripped lower cannot be shipped directly to your home. You must buy one through an FFL. This requires dealing with a background check, sales taxes, and even waiting periods. You are also bound by all gun laws in your state regarding the possession of an AR 15 lower receiver.
The 80% lower is not a firearm!
There are also 80% AR 15 lower receivers that exist. An 80% lower receiver is an unfinished receiver with the area that houses the fire control group unmilled. An 80% AR 15 lower receiver is not actually considered a firearm in the eyes of the United States Federal Government.
Since it is only 80% complete, it cannot accept a fire control group. This means an AR 15 lower receiver that is 80% complete can be shipped directly to your home without having to deal with an FFL, waiting periods or state fees (like the DROS in California).
Of course an 80% AR 15 lower receiver is not a complete firearm. It can't actually go "bang" until you invest a little sweat. The good news is that finishing an AR 15 lower receiver isn't difficult. And, of course, the huge benefit is that you get to build a truly custom, one-off rifle or pistol to your exact specs!
Building vs. buying: The other benefits
Finishing an AR 15 lower receiver also allows you to get to know your rifle inside and out. It gives you a look at how the weapon works, and gives you a deep understanding of how the weapon functions. This allows you to have the knowledge to fix any issues that may arise in the future.
Buying an AR 15 is always an option, but you may be purchasing a configuration you don't really want. You'll have to spend extra money to swap out the parts you don't want for the ones you do. When you build an AR 15 you can choose every part you desire. From the furniture to the trigger. This allows the end user of an AR 15 build to get exactly what they want.
Once you begin working on an 80% AR 15 lower receiver, the ATF considers it a firearm. The ATF does say you can build firearms for personal use without any kind of license. However, once you begin milling your 80% lower, you're not bound by gun laws. Only start building once you're ready to commit to gun ownership.
Now, grab a lower and get started
Building an AR 15 lower receiver is an enjoyable experience that results in something useful, and fun to use. Building an AR 15 lower receiver is a superbly simple task, one that is enjoyable, easy to do, and leaves you with something that goes bang.
Browse our selection of AR-15 Lower Receiver and start your AR-15 build today! https://www.ar-15lowerreceivers.com/collections/80-lower